It will replace Opera’s in-house engine Presto, which turned ten
years old just last month.

The company says that the move to WebKit, which also includes
Chrome’s V8 JavaScript engine, is to allow a refocus on
higher-level features. “Instead of tying up resources duplicating
what’s already implemented in WebKit, we can focus on innovation to
make a better browser,” wrote Opera Web Evangelist Bruce
Lawson.

Due to Opera’s relatively small market share, currently just 1.8%
of the worldwide market by
some measures, it is often ignored by web developers in
compatibility testing. With the same rendering engine as Chrome,
“consumers will initially notice better site compatibility,
especially with mobile-facing sites – many of which have only been
tested in WebKit browsers,” wrote Lawson.

Indeed, all major mobile browsers – the Android stock browser,
Google Chrome, Mobile Safari and now Opera – use WebKit, and as the
market moves away from PCs towards mobile devices WebKit seems
likely to dominate the market.

This under-the-hood change initially will be rolled out to Opera’s
smartphone apps, while Opera Desktop and other products will make
the switch “later”.

For developers, it will mean fewer platforms to test on and no need
for the -o-
prefix on experimental CSS features. However, the window.opera
object will cease to exist in future versions of Opera.

The WebKit engine began life in 1998 as a fork of KDE’s KHTML and
KJS engines to be specifically used in Apple’s flagship web browser
Safari. It was open-sourced in 2005, and
in 2006 adopted by Google Chrome, which has since gone on to
become one of the most popular browsers in the world.